I just went through some stats on murder rates in Europe (developed world), the world in total, and the United States. I'm sure you've seen the headlines of some articles - the US doesn't have a murder problem, it has a guns problem.
Well based on my cursory review of the data on murder rates and guns, its true at the surface level, though not in the way those authors probably wish it to be. The vast majority of our 12,000-14,000 gun murders per year are inner city gang violence. These mass shootings (about 400 murders per year) grab media attention because they happen randomly in our safe corners of the world where we like to hide in our cocoons and not have to be confronted with the rest of the world. But those mass shootings actually comprise a very small percentage (~3%) of the total gun murders in the United States every year. You remove all the shootings in inner cities from the data, and our murder rate (which is already below the world average) then drops well below the developed world average. For example, we had 17,000 murders in the US in 2017. 15,500 of those were with guns. We had 1,500 murders in 2017 that didn't involve guns. There are about 5,000 murders per year in the entirety of Europe...which contains twice our population. So you can see back of the envelope our murder rates are not that different...but for the large problem we have in our cities.